An Assessment of the Role of Sebesi Island as a Stepping-stone for the Colonisation of the Klakatau Islands by Butterflies

Thirty-three butterfly species were collected in July 1993 from Sebesi and Sebuku Islands, Indonesia.Most of them were identified at the subspecies level, except several lycaenids. Fourteen species(42.4%) out of the 33 have never been recorded from the Krakataus. This proportion is distinctly higher than 4 to 8 (13.3 to 26.7%) of 30 species recorded fromSebesi in 1989. When these data were taken together, the percentage becomes 32.7 to 40.4% (17 to 21 of 52 species recorded from Sebesi-Sebuku). Comparison between Javanese and Sumatran subspecies in the rate of common species on Sebesi-Sebuku and the Krakataus indicates that the Butterfly fauna of the Krakataus have been chiefly derived from Java rather than from Sumatra even thought the 2 stepping-stone islands exist between the Krakataus and Sumatra